Re: force-mode-line-update ALL argument

[martin rudalics <rudalics@gmx.at>]

Thank you for your efforts but I don't get it yet :-(

 > By making `other-buffer' the current-buffer we're effectively asking
 > Emacs to select some buffer which is _not_ visible and updating _its_
 > modeline as well if it has changed recently.

What makes you conclude that a `set-buffer' on the value returned by
`other-buffer' causes updating the modeline of a buffer that maybe has
neither been changed nor displayed?

 > An other non-visible
 > buffer on the current frame

What is a non-visible buffer on a frame?  When a buffer is visible it is
on a frame.  When a buffer is not visible it is on no frame.

 > which is not visible but has been modified
 > (a modeline change counting as such)

What is a "modeline change" and how can it modify the buffer or count as
a buffer modification?

 > will tickle the buffer-modified-p
 > predicate

This predicate is set by a buffer change and by nothing else.

 > thereby forcing _all_ non-visible buffers on current frame
 > to have their modeline updated...

The only reason of updating a modeline is when the buffer is visible.

martin, still hoping that someone can shed light on this issue